The present invention relates to an absorption refrigerator. More specifically, the present invention is concerned with an absorption refrigerator in which liquid-film type plate heat exchangers are used for an absorber, an evaporator, a regenerator and a condenser.
An absorption refrigerator is used for various applications, such as air conditioning, supply of cold or hot water., etc. Generally, when an absorption refrigerator is used for air conditioning for a building, it is installed in a basement or on a rooftop. Therefore, it is desired to minimize the volume of the refrigerator as well as the installation area.
This cannot be achieved, however, in an absorption refrigerator in which an evaporator, an absorber, a condenser and a regenerator each have a so-called shell-and-tube type heat exchanger structure, because such a refrigerator has a large volume relative to a heat transfer area. Therefore, a proposal has been made to use, as the evaporator, the absorber, the condenser and the regenerator, a plate type heat exchanger having a high heat transfer efficiency relative to a volume thereof, especially a film-liquid type plate heat exchanger.
However, differing from the shell-and-tube type heat exchanger in which the heat transfer area can be increased as desired by increasing the number of heat transfer tubes or increasing the length of the heat transfer tube (while maintaining the same height), the film-liquid type plate heat exchanger has a problem of imparting a large height to the refrigerator for the following reasons.
When the heat transfer area of the plate is increased by increasing the width of the plate, it is difficult to effect uniform flow of fluid across the entire width of the plate, thus lowering the heat transfer efficiency of the heat exchanger. To avoid such a lowering of the heat transfer efficiency, it is required to elongate the plate in a direction of flow of the fluid. Generally, the plate is vertically oriented so as to effect flow of the fluid efficiently in an upward or downward direction. Therefore, the height of the plate becomes large.
Another reason is as follows. It is assumed to use a liquid-film type plate heat exchanger in a generally rectangular form, in which a liquid supply device (in a rectangular form) is placed on (rectangular) liquid-film type plates for making flow of a liquid over surfaces of the plates. In such a liquid-film type plate heat exchanger, the width of the liquid supply device is required to be increased as the width of the plates is increased, even if the capacity of the heat exchanger is maintained constant. In other words, change in height of the plates does not require any substantial change in the capacity of the liquid supply device. From this point of view, the height of the plate type heat exchanger is made large.
Further, as compared to the shell-and-tube type heat exchanger, the heat-exchange part of the liquid-film type plate heat exchanger can be reduced in size as a whole. However, in a reservoir part for an absorption solution and a cooling medium provided below the absorber and the evaporator, a liquid level substantially varies according to a change in the concentration of the absorption solution. Therefore the height of the reservoir portion must be large.
The height of the absorption refrigerator becomes large mainly for the reasons mentioned above. However, especially when the refrigerator is installed in a basement or on a rooftop of a building for air conditioning, it is advantageous to minimize the height of the refrigerator, for transport and installation. A limit of a practical height of the refrigerator is considered to be about 2,000 mm.
In a so-called double-effect absorption refrigerator including a high-temperature regenerator, when the height of a low-pressure can body (a can body accommodating a low-temperature regenerator, a condenser, an absorber and an evaporator) becomes considerably larger than that of a high-temperature regenerator, much of the space in the refrigerator is wasted and the refrigerator is not suitable for practical use.
In view of the above, it is an object of the present invention to provide a compact absorption refrigerator using liquid-film type plate heat exchangers, in which the height of the refrigerator can be maintained at a practical level while the volume of the refrigerator as a whole is reduced.
In order to achieve the above-mentioned object, the present invention provides an absorption refrigerator comprising an absorber, an evaporator, a regenerator and a condenser, each having a structure of a liquid-film type plate heat exchanger, wherein the absorber, the evaporator, the regenerator and the condenser are arranged in a horizontal direction.
The evaporator, the absorber, the regenerator and the condenser may be accommodated in a single can body, and the evaporator and the absorber, and the regenerator and the condenser may be, respectively, accommodated in different chambers divided by a partition wall provided in the can body.
Specifically, each of the evaporator, the absorber, the regenerator and the condenser may comprise an assembly of parallel plates forming the liquid-film type plate heat exchanger, the plates being arranged in a front-to-rear direction relative to the front of the absorption refrigerator, and the evaporator, the absorber, the regenerator and the condenser may be arranged in a lateral direction.
Each of the evaporator, the absorber, the regenerator and the condenser may comprise an assembly of parallel plates forming the liquid-film type plate heat exchanger, the plates being arranged in a lateral direction relative to the front of the absorption refrigerator; the evaporator and the absorber may be arranged in a front-to-rear direction relative to each other and the regenerator and the condenser may be arranged in the front-to-rear direction relative to each other; and the evaporator and the absorber, and the regenerator and the condenser may be arranged in the lateral direction.
Further, the evaporator and the absorber, and the regenerator and the condenser may be, respectively, accommodated in different can bodies.
Further, each of the evaporator and the absorber may comprise an assembly of vertically oriented parallel plates forming the liquid-film type plate heat exchanger, the respective parallel plates of the evaporator and the absorber being arranged in an alternate fashion in the horizontal direction relative to each other, the evaporator and the absorber being formed as an integral structure.
Each of the regenerator and the condenser may comprise an assembly of vertically oriented parallel plates forming the liquid-film type plate heat exchanger, the respective parallel plates of the regenerator and the condenser being arranged in an alternate fashion in the horizontal direction relative to each other, the regenerator and the condenser being formed as an integral structure.
Cooling water can be supplied to the absorber and the condenser either in parallel or in series in this order.